The present invention relates to a terminal connecting structure, and a terminal connecting method.
In an automobile, many electric or electronic devices are connected to a battery functioning as a power supply, and grounded through a ground terminal fixed to a mount part such as a vehicle body panel. In such a grounding method, a plurality of electric wires constituting electric circuits are assembled (bundled), and connected to the ground terminal by various terminal connecting structures. Terminal connecting structures for the grounding terminal and the like are required to be easily disassembled from viewpoints of: the connection reliability; supplies of requested current and voltage values; prevention of electromagnetic leakage to an adjacent circuit; exclusion of an electric short circuit; the waterproof property; and the like, and further viewpoints of: easiness of the work of mounting to a vehicle; ensuring of the mounting reliability; and resource conservation.
In the attachment structure which is disclosed in JP-A-2007-305362, and in which a ground terminal is fixed to a body panel, as shown in FIG. 7A, for example, electric wires 501 are crimped by wire crimping claws 525 of a ground terminal 523, and thermocompression bonding parts of bare wires are thermocompression bonded to a thermocompression bonding surface 527 of the ground terminal 523. The ground terminal 523 is fixed to the body panel (mount part) 535 by the tightening force of a bolt 529 and a nut 531, and the engaging force exerted by body fixing claws 533. In the ground terminal 523, the crimping force and the thermocompression bonding force are set to be smaller than the fixing force. Therefore, when the electric wires 501 are torn off in a direction perpendicular to the thermocompression bonding surface 527 of the ground terminal 523, the wires 501 can be removed from the body panel 535 without detaching the bolt 529 and the nut 531. It is not necessary to forma fracture groove in the ground terminal 523, and therefore the electric resistance is not increased during energization. Even when the force for removing the wires 501 is set to be small, factors in causing production irregularities are hardly introduced, and easy disassemblability can be readily provided and applied to mass-produced products.
In the waterproofing structure for a waterproofing bolted terminal which is disclosed in JP-A-2008-262787, as shown in FIG. 7B, conductor exposed portions 503 in the tip ends of electric wires 501 are connected to a conductor connecting portion 507 that is formed in one end of a terminal 505, and insulated covering portions 509 of the electric wires 501 are held by an insulated covering holding portion 511 that is formed in the other end of the terminal 505. Crimp pieces 513 which are extended from the upper ends of sidewalls of the insulated covering holding portion 511 are disposed in the both ends of the insulated covering holding portion. On the lateral side of a wire fixing portion 515 configured by the conductor connecting portion 507 and the insulated covering holding portion 511, a bolt tightening plate 517 which is to be fixed to a mating member is projected with being located on the side of the insulated covering holding portion 511. The conductor connecting portion 507, the conductor exposed portions 503, and end portions of the insulated covering portions 509 are immersed in a water sealant 519 to be molded. This causes the water sealant 519 to penetrate gaps between the insulated coverings of the electric wires 501 and conductors 521, and the conductors 521, and the waterproof property is ensured.
In the related-art grounding method in which grounding is performed through a ground terminal fixed to a body panel, as described above, the electric wires 501 are connected to the grounding point (bolt 529) of the body panel 535 (mount part) while collecting the wires 501 by using the ground terminal 523, or to the body (mount part) while collecting the wires 501 by using a joint (a bonder or a joint connector). In the related-art grounding method, namely, a terminal connecting structure such as a grounding terminal is used, and the electrical connection to the minus terminal of a battery is conducted through the body.
When the water sealant 519 is to be disposed in the conductor connecting portion 507 where the conductor exposed portions 503 of the wires 501, and the terminal 505 are connected (by thermal welding or ultrasonic connection) to each other, however, the water sealant 519 must be disposed only in the conductor connecting portion 507. Therefore, masking steps or the like must be usually added, and hence the production cost is increased. In the waterproofing structure shown in FIG. 7B, the terminal 505 cannot have a configuration where the bolt tightening plate 517 is disposed at the tip end.